17-4 H1075 to H900 Condition
17-4 H1075 to H900 Condition
(OP)
Hi Team,
Recently our customer request for 17-4 H900 part. We use material 17-4 H1075 & did solution annealed and HT to H900 condition.
Once we done annealing & HT to H900 Condition, will be the material yield strength and tensile strength as per H900 or different from H900 mechanical properties?
Please advise.
Thanks.
Recently our customer request for 17-4 H900 part. We use material 17-4 H1075 & did solution annealed and HT to H900 condition.
Once we done annealing & HT to H900 Condition, will be the material yield strength and tensile strength as per H900 or different from H900 mechanical properties?
Please advise.
Thanks.





RE: 17-4 H1075 to H900 Condition
It should be H900, if you did everything correctly.
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P.E. Metallurgy, Plymouth Tube
RE: 17-4 H1075 to H900 Condition
RE: 17-4 H1075 to H900 Condition
In the PH grades you get grain refinement with re-heattreating.
The other main fault is not cooling low enough and fast enough between anneal and age.
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P.E. Metallurgy, Plymouth Tube
RE: 17-4 H1075 to H900 Condition
The HT process as below,
Base material 17-4 H1075, Required 17-4 H900...
Annealing @ 850°C for 2 Hours
Quenching @ 1020°C for 2.5 Hrs (Gas Cooling)
Tempering 1 @ 480°C for 3 Hrs & Tempering 2 @ 475°C for 3Hrs to achieve hardness Min 40HRC.
Please advise.
RE: 17-4 H1075 to H900 Condition
1900F +/-25F for 30 min (once temp is reached)
cool to below 90F within 1 hour
age 900F +/-10F for 4 hours
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P.E. Metallurgy, Plymouth Tube
RE: 17-4 H1075 to H900 Condition
RE: 17-4 H1075 to H900 Condition
At 950 the limit is a bit over 2hrs, at higher temps you don't really want to go beyond 1hr or you will start reducing properties.
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P.E. Metallurgy, Plymouth Tube
RE: 17-4 H1075 to H900 Condition
what is the need for 850C anneal? Also, why aging twice? I see no benefit from these two additional HT.
RE: 17-4 H1075 to H900 Condition
And I hadn't converted the anneal temp, I hope that the 850C was a typo because it won't work.
You can re-anneal and re-age these alloys over and over. You will loose a small amount of strength (compensate by lowering aging 25F) but the toughness should improve (as the grain size gets finer)
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P.E. Metallurgy, Plymouth Tube
RE: 17-4 H1075 to H900 Condition
Your definition of the process, with the exception of certain testing protocols for load coupons, is in-line-with AMS2759/3.
NOTE, for aerospace: MIL-HDBK-1587 MATERIALS AND PROCESS REQUIREMNTS FOR AIR FORCE WEAPON SYSTEM, Table 1 Restricted Materials, indicates that 17-4PH HT to H900 and H925 [and sometimes H950] are generally prohibited... mostly due to poor SCC, low fracture toughness and possibly premature elevated temperature corrosion issues.
Regards, Wil Taylor
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